Causes

Destroying foreign substances. Eosinophils can consume foreign substances — particularly substances related to infection with a parasite — that have been "flagged" for destruction by other components of your immune system.

Regulating inflammation. Eosinophils help promote inflammation, which plays a beneficial role in isolating and controlling a disease site. But, sometimes inflammation may be greater than is necessary, which can lead to troublesome symptoms or even tissue damage. For example, eosinophils play a key role in the symptoms of asthma and allergies, such as hay fever. Other immune system disorders also can contribute to ongoing (chronic) inflammation.

Eosinophilia occurs when either a large number of eosinophils are recruited to a specific site in your body or bone marrow produces too many eosinophils. This can be caused by a variety of conditions, diseases and factors, including:

Parasitic and fungal diseases

Allergies, including to medications or food

Adrenal conditions

Skin disorders

Toxins

Autoimmune diseases

Endocrine disorders

Tumors

Specific diseases and conditions that can result in blood or tissue eosinophilia include:

Parasitic diseases and allergic reactions to medication are among the more common causes of eosinophilia. Hypereosinophilic syndrome tends to have an unknown cause or results from certain types of cancer, such as bone marrow or lymph node cancer.

Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.

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